The invention relates to an X-ray system for imaging the head and neck regions of the human anatomy including both static and tomographic modalities utilizing a limited output stationary anode X-ray tube system.
The system is designed with emphasis on installation in the offices of private practitioner, for example the dental profession, for utilization in projecting cranial images. Specifically, the images projected can be static images of the head and neck region of anatomy with emphasis on the tomographic projection of the temporomandibular joint and the maxilla-mandibular areas for the projection of osseus integrated implant sites. A specific aspect of this invention relates to the dental implant and to X-ray tomography as supporting the dental implant system in providing tomographic X-rays of selected implant sites, and is illustrative of one of the more difficult areas of anatomy to position for an accurate tomographic projection and is described here as an example. More particularly, this aspect of the invention is concerned with a positioning system, apparatus and method for precisely locating the patient in X-ray tomography such that the site of the anatomy of interest is at the correct position to provide an accurate tomographic X-ray projection.
Regarding the specific dental implant aspect of the invention the dental profession has been involved to an increasing degree with the osseus integrated implant system to facilitate dental prosthesis. In order to properly install an implant, an X-ray of the proposed site should be taken so that the dentist can investigate the adequacy of the osseus tissue to support an implant post at that site.
The X-ray of the mandible or maxilla should employ tomography in order to project the cross sectional area of the mandible or maxilla at the site. The site, i.e. the anatomy of interest, must be accurately positioned in the tomographic plane and in the central beam axis or isocenter of rotation of the X-ray in order to obtain the desired cross sectional image at the site.
X-ray tomography, as is well known, involves the constant movement of an X-ray source and photographic plate relative to the patient during exposure of the X-ray image. The X-ray source and plate rotate through an arc in which the X-ray beam continuously intersects a central axis or fulcrum plane axis at a focal point. The result is that all bone structure in front of and behind the plane of interest (i.e. on the sides toward and away from the plane of interest) are blurred and essentially do not appear in the image. Only that structure located at the fulcrum plane, i.e. a thin plane of bone structure, appears in the X-ray, so that the image is of a cross section of the bone tissue. The wider the arc of movement of the X-ray source during exposure, the thinner and more specific the depth of the resulting cross sectional image.
A problem for dentists practicing implant prosthesis has been the lack of a convenient, accurate, reliable and affordable source for obtaining X-ray tomographic sectional-plane images of proposed mandible or maxilla sites for implant. Generally the patient has been sent to a radiologist with instructions to investigate certain sites. The radiologist usually employs Computerized Axial Tomography ("CAT Scan") to project the necessary views. As a consequence, the procedure has involved an additional facility requiring separate scheduling and does not provide the immediacy of information desired, not to mention the radiation dosage and cost of the examination.
Previous to the present invention there has not been an accurate and convenient system that can be installed in a private office for correctly positioning a patient for X-ray tomographic imaging of potential dental implant sites such that in most cases, a single exposure and image can be taken for each location of interest.